diff --git a/pkgs/build-support/rust/build-rust-package/default.nix b/pkgs/build-support/rust/build-rust-package/default.nix
index 95b6f357e56a..db0d2c53bb1e 100644
--- a/pkgs/build-support/rust/build-rust-package/default.nix
+++ b/pkgs/build-support/rust/build-rust-package/default.nix
@@ -52,8 +52,9 @@
 , buildAndTestSubdir ? null
 , ... } @ args:
 
-assert cargoVendorDir == null && cargoLock == null -> !(args ? cargoSha256) && !(args ? cargoHash)
-  -> throw "cargoSha256, cargoHash, cargoVendorDir, or cargoLock must be set";
+assert cargoVendorDir == null && cargoLock == null
+    -> !(args ? cargoSha256 && args.cargoSha256 != null) && !(args ? cargoHash && args.cargoHash != null)
+    -> throw "cargoSha256, cargoHash, cargoVendorDir, or cargoLock must be set";
 assert buildType == "release" || buildType == "debug";
 
 let
diff --git a/pkgs/build-support/rust/fetch-cargo-tarball/cargo-vendor-normalise.py b/pkgs/build-support/rust/fetch-cargo-tarball/cargo-vendor-normalise.py
index 2d7a18957184..90933b089c92 100755
--- a/pkgs/build-support/rust/fetch-cargo-tarball/cargo-vendor-normalise.py
+++ b/pkgs/build-support/rust/fetch-cargo-tarball/cargo-vendor-normalise.py
@@ -13,7 +13,9 @@ def quote(s: str) -> str:
 def main() -> None:
     data = toml.load(sys.stdin)
 
-    assert list(data.keys()) == ["source"]
+    # There is no dependency to vendor in this project.
+    if not list(data.keys()) == ["source"]:
+        return
 
     # this value is non deterministic
     data["source"]["vendored-sources"]["directory"] = "@vendor@"
diff --git a/pkgs/build-support/rust/fetch-cargo-tarball/default.nix b/pkgs/build-support/rust/fetch-cargo-tarball/default.nix
index 2f1f3547dbb0..6d6219078bac 100644
--- a/pkgs/build-support/rust/fetch-cargo-tarball/default.nix
+++ b/pkgs/build-support/rust/fetch-cargo-tarball/default.nix
@@ -58,10 +58,21 @@ in stdenv.mkDerivation ({
     export CARGO_HOME=$(mktemp -d cargo-home.XXX)
     CARGO_CONFIG=$(mktemp cargo-config.XXXX)
 
+    if [[ -n "$NIX_CRATES_INDEX" ]]; then
+    cat >$CARGO_HOME/config.toml <<EOF
+    [source.crates-io]
+    replace-with = 'mirror'
+    [source.mirror]
+    registry = "$NIX_CRATES_INDEX"
+    EOF
+    fi
+
     ${cargoUpdateHook}
 
-    cargo vendor $name | cargo-vendor-normalise > $CARGO_CONFIG
+    cargo vendor $name --respect-source-config | cargo-vendor-normalise > $CARGO_CONFIG
 
+    # Create an empty vendor directory when there is no dependency to vendor
+    mkdir -p $name
     # Add the Cargo.lock to allow hash invalidation
     cp Cargo.lock.orig $name/Cargo.lock
 
@@ -81,7 +92,7 @@ in stdenv.mkDerivation ({
 
   inherit (hash_) outputHashAlgo outputHash;
 
-  impureEnvVars = lib.fetchers.proxyImpureEnvVars;
+  impureEnvVars = lib.fetchers.proxyImpureEnvVars ++ [ "NIX_CRATES_INDEX" ];
 } // (builtins.removeAttrs args [
   "name" "sha256" "cargoUpdateHook" "nativeBuildInputs"
 ]))
diff --git a/pkgs/tools/misc/elfcat/default.nix b/pkgs/tools/misc/elfcat/default.nix
index e2dec357d6d2..359bd6d3ab93 100644
--- a/pkgs/tools/misc/elfcat/default.nix
+++ b/pkgs/tools/misc/elfcat/default.nix
@@ -11,8 +11,7 @@ rustPlatform.buildRustPackage rec {
     sha256 = "sha256-NzFKNCCPWBj/fhaEJF34nyeyvLMeQwIcQgTlYc6mgYo=";
   };
 
-  # There is no dependency to vendor in this project.
-  cargoLock.lockFile = ./Cargo.lock;
+  cargoHash = "sha256-Dc+SuLwbLFcNSr9RiNSc7dgisBOvOUEIDR8dFAkC/O0=";
 
   meta = with lib; {
     description = "ELF visualizer, generates HTML files from ELF binaries.";